seemly one or another the printing press of hubris comics is still working (?), and there are also lots of computers suprisingly still working, amongst lights in the metro system, so it shouldn't be to hard to set up a deal of making more paper money. I'f they can purify radiated water it shouldn't be to hard, I have seen plenty eggheads and technicians in the game who do more difficult things (like the mechanizer with his robot army)

I'm surprised the pre-war money doesn't hold more value. You'd think that there'd be some sentimental value to it, thus boosting its worth.

It's a crazy, messed up world.

if you think about it... coins today are made of zinc in the interior, simply with a nickel or copper coating whereas bottle caps are currently all aluminum. zinc+weather=bad... aluminum+pretty much anything?=not much zinc wont last 200 years. much less a nuclear fallout, aluminum on the other hand might have a chance

This is an explanation I came to.

It is not a rare thing for countries to request their population to hand in unused steel.
Chairman Mou did it, the Weimar Republic did it.

I believe that before the great war the American goverment asked for all the bottlecaps taken off of Nuka Cola bottles to be handed in to the goverment instead of being thrown away. In exchange for the bottle caps the goverment would re-emburse the citizens for thier help to the war effort.
This would give bottle caps a value n the American psyche, much like in britain you can purchase items with stamps you would be able to purchase cheap items with LOTS of bottle caps. However after the war flimsey paper money would be destroyed, where as the bottle caps would be still around to use as money.

Anyway thats my take on things.

Well, to make dollar bills you have to have the nylon, cotton, paper, etcetera they have to have for it. While bottlecaps were already around everywhere on bottles, in the lakes, etc. so they didn't really have to get as much to make them because there was probably so much, that when everyone gets all of them, there's enough to last due to circulation.
Also, they still make Nuka-Cola's I presume, so it's never ending I guess. =P

Maybe on the east coast the reason for caps being used is because the Nuka Cola plant is there, and there is plenty like others have said.